Hard to believe you could screw up something so easy!

There are many ways of iterating over lists in C++/Qt.
In the specific case of QStrings, it is known [1] that using
foreach with const references avoids the creation of new
QString objects in each iteration, reducing the time consumed
by the loops.

[1] https://blog.qt.io/blog/2009/01/23/iterating-efficiently/Signed-off-by: Anselmo L. S. Melo <anselmo.melo@intel.com>

Plus notify user

Instead us a Toolbox concept which hangs off of QGCApplication

- Also added new adjustMavlinkMessage support

- MultiVehicleManager is a Qml friendly replacement for UASManager
- Vehicle is a replacement for both UAS and AutoPilotPlugin

Also fixed case where UASMessageHandler reported errors but walking
list turned up no errors

Was causing unnecessary read re-requests to get sent out

QGCUASParamManager and friends are replaced by FactSystem